Originally Posted by kschachn
Originally Posted by StevieC
Amsoil has served me well but both oils are good oils.
While Amsoil hasn't officially licensed their oils in the Signature Series they do have testing that they have met the requirements as specified.
For at least some of the Amsoil products it cannot be dexos licensed since it exceeds the maximum sulfated ash permitted by dexos. So it does not meet "the requirements as specified":
https://www.amsoil.com/lit/databulletins/g2880.pdf
Quote
Fortified with detergents that exceed the dexos 1 Gen 2 sulfated ash specification
I clearly said they did their own testing. Just because GM thinks the sulfated ash is a problem doesn't mean that an Oil with it actually is.
This is GM after all, the OE that had to come out with an oil specification to fix their engineering woes when timing chains have been around forever and got by just fine on garden variety oils in the past.
If Amsoil says their oils will work where Dexos requirements are needed as they specify on their PDS then I trust them based on my previous experiences with the product. Many other folks do as well. They are not going to stake decades of word of mouth reputation on anything that wouldn't live up to the task and if they did we would see tons of people complaining and lawsuits and that isn't happening.
I did preface my statement above saying if you want actual licensing to sleep at night for fear of warranty denial then so be it.
The OP doesn't seemed concerned with this so I answered his question based on this.
Why does every thread need to go off about buying an off the shelf oil when that wasn't the question that was asked? (This part is not aimed at you KS)